This invention relates to a supporting and holding mechanism for use in an image forming apparatus, such as a copying machine, which is adapted to hold a roll of paper with flange members connected to both ends of the roll of paper, and more particularly to a holding device which can be easily engaged with both ends of a roll of paper and which can positively support the roll of paper.
In general, an image forming apparatus, such as a copying machine or a printer, employs sheet supplying means in which a number of sheets of paper cut to a predetermined size are accommodated in a sheet accommodating means, such as a sheet supplying cassette or a sheet tray.
On the other hand, an electronic copying machine or a facsimile system, which may require large sheets of paper, employs a cutting device together with a roll of paper so that a recording sheet can be formed freely according to the size of a given original.
In a copying machine disclosed, for instance, by Japanese Patent Application (OPI) No. 220657/1989 (the term "OPI" as used herein means an "unexamined published application"), a plurality of rolls of paper are loaded in the sheet supplying section. The rolls thus loaded may be of tracing paper, ordinary paper, etc. In response to the kind of paper selected by the operator and the size of an original, one of the rolls of paper is selected, and a sheet of paper is supplied from the roll thus selected to the image transferring section.
In addition, in the conventional copying machine, a cutter or the like is provided at the sheet supplying section, to cut the paper thus supplied to a necessary length.
In the copying machine thus constructed, a roll of paper is set in the sheet supplying section, as follows. A supporting shaft is inserted into the roll of paper, and both ends of the supporting shaft are supported with supporting members provided on both sides of the sheet supporting section.
Tensioning means is provided for the supporting shaft or the roll of paper at a predetermined part, so that the sheet supplying operation is carried out under a predetermined tension value irrespective of the amount of paper remaining in the roll.
The above-described sheet supplying unit, which uses rolls of paper, is disadvantageous for the following reason. When it is required to insert the supporting shaft into a roll of paper which is larged in size, such as a roll of paper of A0 size, the work cannot be performed without a large space, and the work itself is troublesome.
On the other hand, a method has been employed by a facsimile system or the like in which flange members are engaged with both ends of a roll of paper, and the flange members thus engaged are rotatably supported on supporting members.
In this case, generally the flange members each comprise: a flange large in diameter; and a pipe-shaped portion extended from the flange. The pipe-shaped portions are inserted into the core of a roll of paper, and the flanges are rotatably positioned on the supporting members. In order to accurately position the flanges on the supporting members, it is necessary to provide supporting means corresponding to the size of paper; however, the provision of the supporting means may make the sheet supplying section intricate in construction.
Furthermore, the employment of the above-mentioned members may suffer since the pipe-shaped portions are not always sufficiently engaged with the core of the roll of paper; that is, it is difficult for the pipe-shaped portions to positively support the roll of paper at all times.